Impacting machines of this type generally have a tool holder in which a tool can be releasably fitted for limited axial reciprocation with respect to the tool holder. A hammering mechanism generates repeated impacts on the rearward end of the tool. The forward end of the tool is urged against a material to be broken up, such as rock or concrete and the tool transfers the impacts from the hammering mechanism to the material. The tool is generally held within the tool holder by a locking member which engages a retaining collar formed on the tool.
GB1,382,019, describes an impacting machine with a tool holder for a tool with such a retaining collar. In a first embodiment a latch is pivotally mounted on the tool holder, to pivot between a first position in which a projection on the latch is engageable with the collar to maintain the tool within the tool holder and a second position in which the projection is moved out of the path of the collar. The latch is releasably locked in the first position by the latch snap fitting between a pair of lugs, which lugs are made out of a resilient material. With the latch in the second position the tool can be removed from the tool holder and replaced by another tool. In a second embodiment a latch is slideably mounted within the tool holder between a first position in which a projection on the latch is engageable with the collar to maintain the tool within the tool holder and a second position in which the projection is moved out of the path of the collar. The latch is maintained in the first position by the snap fitting of a resilient collar within an annular recess formed on the latch. Both the embodiments require a user to use his or her feet to move the latch from the first position to the second position. Therefore, it is difficult to operate the latch of known tool holder designs for impacting machines which are fitted with tools having a collar.